Ambon Island is part of the Maluku Islands of Indonesia. The island has an area of 775 km2 (299 sq mi), and is mountainous, well watered, and fertile. Ambon Island consists of 2 territories: The main city and seaport is Ambon (2009 pop. 284,809), which is also the capital of Maluku province and Maluku Tengah (2009 pop. 370,931. Ambon has an airport, and are home to the Pattimura University and Open University (Universitas Terbuka), state universities, and a few private universities, which include Darussalam University (Universitas Darussalam, UNDAR) and Universitas Kristen Indonesia Maluku (UKIM).

Ambon Island lies off the south-west coast of the much larger Seram island. It is on the north side of the Banda Sea, part of a chain of volcanic isles that form a circle around the sea. It is 51 km (32 mi) in length, and is of very irregular shape, being almost divided into two. The south-eastern and smaller portion, a peninsula (called Leitimor) is united to the northern (Hitoe) by a narrow neck of land. Ambon city lies on the north-west of Leitimor, facing Hitoe, and has a safe harbor on Amboina Bay.

The highest mountains, Wawani 1,100 m (3,600 ft) and Salahutu 1,225 m (4,019 ft), have hot springs and solfataras. They are volcanoes, and the mountains of the neighboring Uliaser islands, extinct volcanoes. Granite and serpentine rocks predominate, but the shores of Amboina Bay are of chalk, and contain stalactite caves.

Wild areas of Ambon Island are covered by tropical rainforest, part of the Seram rain forests ecoregion, together with neighboring Seram. Seram, Ambon, and most of Maluku are part of Wallacea, the group of Indonesian islands that are separated by deep water from both the Asian and Australian continents, and have never been linked to the continents by land.

As a result of this isolation, Ambon has few indigenous mammals; birds are more abundant. The insect diversity of the island, however, is rich, particularly in butterflies. Seashells are obtained in great numbers and variety. Tortoise-shell is also exported. The population of the island (administered as Kota Ambon, Kecamatan Leihitu, Kecamatan Leihitu Barat, and Kecamatan Salahutu) includes a tiny sparsely populated island to the north, is just shy of 441,000 in the 2010 Census.